This study examines the effects of social capital on firm voluntary disclosure. We find that firms headquartered in the U.S. counties with higher levels of social capital provide more management forecasts than firms in the counties with lower levels of social capital. We further find that this positive effect is driven mainly by two factors in social capital, which are the social associations, especially those actively seeking their preferential policies, and voter turnout. The positive effect of social capital is more pronounced in firms of smaller size, firms with more local employees, higher sales growth rates, and good earnings performance. Overall, these results suggest that social capital, especially social associations and community proactivity, promotes firm voluntary disclosure.